# Copyright (C) 2012-2014 Bastian Kleineidam
"""
Functions to load plugin modules.
Example usage::
modules = loader.get_package_modules('plugins')
plugins = loader.get_plugins(modules, PluginClass)
"""
import os
import importlib.util
import pkgutil
from .fileutil import is_writable_by_others
[docs]
def check_writable_by_others(filename):
"""Check if file is writable by others on POSIX systems.
On non-POSIX systems the check is ignored."""
if os.name != 'posix':
# XXX on non-posix systems other bits are relevant
return
return is_writable_by_others(filename)
[docs]
def get_package_modules(packagename, packagepath):
"""Find all valid modules in the given package which must be a folder
in the same directory as this loader.py module. A valid module has
a .py extension, and is importable.
@return: all loaded valid modules
@rtype: iterator of module
"""
for mod in pkgutil.iter_modules(packagepath):
if not mod.ispkg:
try:
name = f"..{packagename}.{mod.name}"
yield importlib.import_module(name, __name__)
except ImportError as msg:
print(_("WARN: could not load module %s: %s") % (mod.name, msg))
[docs]
def get_folder_modules(folder, parentpackage):
"""."""
if check_writable_by_others(folder):
print("ERROR: refuse to load modules from world writable folder %r" % folder)
return
for filename in get_importable_files(folder):
fullname = os.path.join(folder, filename)
modname = parentpackage + "." + filename[:-3]
try:
spec = importlib.util.spec_from_file_location(modname, fullname)
module = importlib.util.module_from_spec(spec)
spec.loader.exec_module(module)
yield module
except ImportError as msg:
print(_("WARN: could not load file %s: %s") % (fullname, msg))
[docs]
def get_importable_files(folder):
"""Find all module files in the given folder that end with '.py' and
don't start with an underscore.
@return: module names
@rtype: iterator of string
"""
for fname in os.listdir(folder):
if fname.endswith('.py') and not fname.startswith('_'):
fullname = os.path.join(folder, fname)
if check_writable_by_others(fullname):
print(
"ERROR: refuse to load module from world writable file %r"
% fullname
)
else:
yield fname
[docs]
def get_plugins(modules, classes):
"""Find all given (sub-)classes in all modules.
@param modules: the modules to search
@type modules: iterator of modules
@return: found classes
@rtype: iterator of class objects
"""
for module in modules:
yield from get_module_plugins(module, classes)
[docs]
def get_module_plugins(module, classes):
"""Return all subclasses of a class in the module.
If the module defines __all__, only those entries will be searched,
otherwise all objects not starting with '_' will be searched.
"""
try:
names = module.__all__
except AttributeError:
names = [x for x in vars(module) if not x.startswith('_')]
for name in names:
try:
obj = getattr(module, name)
except AttributeError:
continue
try:
for classobj in classes:
if issubclass(obj, classobj):
yield obj
except TypeError:
continue